1. Field of the Invention
The present invention relates to a battery chamber or battery holder for electronic equipment such as a camera and its accessories, and a reverse voltage prevention mechanism therefor.
2. Related Background Art
In general, in various kinds of equipment such as a camera which uses a battery as a power supply, in order to store and hold a battery, a battery chamber is directly arranged in an equipment main body, or a space portion is formed in the equipment main body, and a battery holder is inserted/removed into/from this space portion.
FIG. 6 shows a battery holder which is inserted/removed into/from the space portion formed in the equipment main body when it is used. In this battery holder, side walls 2 and 3 are formed on a holder main body 1 to be separated by a predetermined interval, and a battery storage portion 5 for storing two elongated batteries 4 is formed between these side walls 2 and 3.
A battery contact spring member 6 which contacts the electrodes of the batteries 4 is disposed at the side wall 3 side in the battery storage portion 5.
First and second press-down members 7 and 8 are disposed at the two sides of the battery storage portion 5 to be separated by a predetermined distance. The first and second press-down members 7 and 8 respectively extend toward the battery 4 side, and press and hold the outer surfaces of the batteries 4.
In this battery holder, as shown in FIG. 6, each battery is stored in the battery storage portion 5 in such a manner that the battery contact spring member 6 is pressed down by one end face of the battery 4 in a state wherein the battery contact spring member 6 side of the battery 4 is inclined downward, and thereafter, the battery 4 is set in a horizontal state parallel to the bottom surface of the battery storage portion 5.
However, in this conventional battery holder, when the battery 4 is set in the horizontal state, the battery 4 contacts the second press-down member 8 extending toward the battery 4 side, and the second press-down member 8 is plastically deformed inwardly. Then, it becomes difficult to store the battery 4.
A conventional battery storage device for a camera and accessories normally uses a leaf spring as its battery contact piece, and a bent portion is formed to assure a given spring force amount and stroke.
A user inserts a battery into the battery storage device while confirming the plus and minus directions of the battery according to the display contents indicated in a battery chamber. In this case, the way of insertion via an opening portion varies depending on user's favors.
In the above-mentioned prior art, upon insertion of a battery into the battery chamber, if insertion of the battery to the battery contact piece, which is elastically deformable, is performed later, the battery contact piece is pushed by the battery, and may be permanently deformed.
Some conventional battery storage portions for a camera and accessories have a reverse voltage (i.e., application of a voltage with the inverse polarity) prevention mechanism for preventing a circuit from being destroyed even when a battery is inserted with inverse polarity. For example, the following mechanism is known. As shown in FIG. 12, projections 230 are formed at the two edges of a battery contact piece at the plus end so as to allow easy assembling, and a U-shaped insulating member having openings is mounted on the contact piece, so that the projections of the battery piece are fitted in the openings. When a battery is inserted with correct polarity, the height of plus-end projection of the battery is larger than the thickness of the insulating member, and the outer diameter of this projection is smaller than the inner width of the U-shaped portion of the insulating member. With this mechanism, when a battery is inserted with correct polarity, the plus-end projection of the battery is electrically connected to the battery contact piece; when the battery is inserted with inverse polarity, the minus end of the battery is blocked by the insulating member and cannot be electrically connected to the battery contact piece.
In the above-mentioned prior art, when a battery is inserted from the above, a force acts in a direction to widen the insulating member, and the insulating member is widened beyond the width of the projections of the battery contact piece. As a result, the insulating member may disengage from the battery contact piece.